Backstepping control of PMSM position systems based on terminal-sliding-mode load observer

For the problem of low control precision,and the low response speed of permanent magnet synchronous motor( PMSM) position control system in the presence of load disturbance,a backstepping control method based on terminal sliding mode load observer was proposed. Firstly,a terminal-sliding-mode load observer which improves the observer convergence rate was designed to estimate load torque. It improves the control precision of the system. Then,a position controller based on nonsingular terminal sliding mode and backstepping was designed. The proposed position controller has good dynamic and static performance,which enhances the robustness,Finally,through the method of Lyapunov stability demonstrated the stability of the system. The simulation results show that observer estimate the load torque quickly and accurately,and the position controller also tracks the given signal effectively.